Buchanan stewart paterson



(No Model.)

. B. S. PATERSON. OOMMUTATOR FOR DYNAMO ELECTRIC MACHINES 0R MOTORS. No.495,561.

Patented Apr. 18, 1893.

UNITED- STATES PATENT OFFICE.

BUCHANAN STEIVART PATERSON, OF GATESHEAD, ENGLAND, ASSIGNOR TO CLARKE,CHAPMAN d7 CO., OF SAME PLACE.

COMMUTATOR FOR DYNAMO-ELECTRIC MACHINES OR MOTORS.

SPECIFICATION forming part of Letters Patent No. 495561, dated April 18,1893.

Application filed August 16, 1892. Serial No.44 3,2'7'7- (N0 model.)Patented in England April 14,1892, No. 7,237, and in France August 13,1892,1Io. 225,066-

To (0% whom it may concern.-

Be it known that I, BUCHANAN STEWART PATERsoN, a subject of the Queen ofGreat Britain and Ireland, residing at Gatesheadon-Tyne, in the countyof Durham, England, have invented Improvements in Commutators forDynamo-Electric Machines or Motors, (for which Letters Patent of GreatBritain,

No. 7,237, dated April let, 1892, and of France,

No. 225,066, dated August 13, 1892, were granted to me and JohnBrokenshire Furneaux,) of which the following is a specification.

My invention has reference to the construction of commutators for dynamoelectric machines. The strips of mica now commonly employed to insulatelongitudinally the metal strips of commutators are usually keyedtogether by lipped flanges and rings, between which and the variousstrips there are interposed layers of comparatively soft material suchas asbestos, boxwood, vulcanized fiber, or compressed paper;consequently any sections of the commutator receiving an accidental blowhave been liable to become sunk below the circumference of thecommutator. This has been found to occur for instance when puttingarmatures into machines where no proper lifting means have existed; ifunder these circumstances the armature has happened to be slung by thecommutator, the great weight of the core has sometimes been sufficientto force the segments out of truth. Furthermore the materials ordinarilyemployed as above set forth are all liable to change form and tocontract by heating; conseqnentiy, although by proper baking in an oventhe insulation resistance could be made very high, it would dropenormously as the result of exposure to moisture.

Now in order to obviate the evils above indicated according to myinvention annular grooves are formed in the flange and ring on thecommutator core or body between which the metal strips and insulatingstrips of the commutator are arranged; in the ends of the annulus ofstrips corresponding grooves are formed, and in these grooves areinserted keys made of mica; and in order that others skilled in the artto which my invention pertains may be enabled to make and use the same Ipro ceed to explain the manner of carrying it into practical effect byreference to the accompa nying drawings, wherein- Figure l is a viewhalf in end elevation and half in cross section of a commutatoraccording to my invention. Fig. 2 is a part central longitudinal sectionof same. Fig. 3 is a view corresponding to Fig. l, but illustrating amodification in which the mica key is composed of strips arrangedcircumferentially.

a is the commutator core or body; I) the flange thereof, formed with anannular groove in its inner face as shown.

0 is the ring formed with a like annular groove.

d d are the metal strips and e e the insulating strips arranged on thecommutator body; the ends of the compound annulus composed of thesestrips being formed as shown each with an annular groove so as to formwith the grooves in the flange and ring key ways to receive the micakeysff. In Figs. 1 and 2 theyare shown composed of rectangular pieces ofmica placed radially in the key ways; but a key may be made of strips ofmica placed circumferentially as in Fig. 3. Between the ends of thecommutator strips (metal and mica) and the flange and ring areinterposed washers g that are also made of mica.

Commutators constructed with mica keys as described will be foundexceedingly strong and even able to resist blows without the solidity ofthe mica being seriously affected; furthermore the constructiondescribed presents manufacturing facilities and affords high insulationresistance even when the commutator is damp.

That I claim is- 1. A commutator, for dynamo electric machines ormotors, constructed with key ways and with keys of mica arranged withinsaid key ways, substantially as described.

2. A commutator for a dynamo electric machine or motor constructed withkey ways and with keys composed of pieces of mica placed radially withinsaid key ways.

3. A commutator for a dynamo electric machine or motor comprising aflange and a ring on the commutator core body both formed with annulargrooves metal strips and insuname to this specification in the presenceof lating strips arranged between said flange and two subscribingwitnesses.

ring and made with corresponding grooves, BUCHANAN STEWART PATERSON.thus forming key ways, and annular keys WVitnesses: 5 composed of piecesof mica placed radially ALFRED LINDSAY FORS'IER,

within said key Ways substantially as de- 28 Uocttsworth Road,Gateshead-on-Tyne. scribed for the purpose specified. JAMES MOLEOD,

In testimony whereof I have signed my 110 [Itgh West Street,Gateshead-mtTyne.

